From owner-freebsd-performance@FreeBSD.ORG Tue Oct 18 21:11:59 2005 Return-Path: X-Original-To: freebsd-performance@freebsd.org Delivered-To: freebsd-performance@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2A64416A41F; Tue, 18 Oct 2005 21:11:59 +0000 (GMT) (envelope-from markus.kovero@multiwise.fi) Received: from smtp.netsonic.fi (smtp.netsonic.fi [194.29.192.26]) by mx1.FreeBSD.org (Postfix) with ESMTP id C1DED43D45; Tue, 18 Oct 2005 21:11:58 +0000 (GMT) (envelope-from markus.kovero@multiwise.fi) Received: from [172.16.0.77] (paradox.fiveam.org [81.17.198.67]) by smtp.netsonic.fi (Postfix) with ESMTP id C27261F803D; Wed, 19 Oct 2005 00:11:57 +0300 (EEST) Message-ID: <43556504.10603@multiwise.fi> Date: Wed, 19 Oct 2005 00:11:32 +0300 From: Markus Kovero User-Agent: Mozilla Thunderbird 1.0.2 (X11/20050731) X-Accept-Language: en-us, en MIME-Version: 1.0 To: freebsd-smp@freebsd.org, freebsd-performance@freebsd.org Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: SMP causes weird performance problems X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Oct 2005 21:11:59 -0000 Hi everyone, basically I've encountered very strange (for me atleast) performance problem while tuning Dell Poweredge 1800. I got 4-disk RAID5 set with harware controller made by Adaptec (works with aac) and everything is fine until I recompile kernel with SMP support. There are 2x Xeon CPU's with hyperthreading enabled (tried htt disabled too) but after SMP turned on disk reads are affected somehow and reads drop 320-350MB/s (with small files <1GB) to 110-150MB/s. Disk writes slow down 1-2MB/s but thats acceptable for me. Mainly I played around with dd but investigated it with bonnie++ too and noticed same behaviour. After that, removed RAID5 array, tried RAID10 (no win) and then even with single volumes. No help, disk reads slow down dramatically after turning SMP on. There's no problem whatsoever SMP turned on or not in linux, reads and writes are snappy. I just don't want linux. Ever. Again. (guys easily drawn into flame wars dont read that last one:) I've tried FreeBSD 5.4 and 6.0_BETA5, with and without adaptive_giant (I read it may cause great slowdowns). Any ideas, suggestions..? Yours Markus Kovero (mui)